The production of ozone involves the addition of an oxygen atom to an oxygen molecule to produce O3 from O2. The ozone molecule is very unstable and easily disposes of one oxygen atom when it reacts with a carbon containing molecule. This makes ozone a strong oxidizer. Commercially, ozone is used as a bactericide, e.g., for treatment of water systems. In addition, ozone has been used to increase the efficiency of internal combustion engines and, at the same time, eliminate unhealthy emissions from such engines, including non-combusted fuel vapor and fuel particles, carbon monoxide, and nitrogen oxides.
Ozone can be produced using a variety of methods, although the corona discharge method predominates in the ozone generation industry. The corona discharge method involves passing an oxygen containing gas through two electrodes separated by a dielectric and a discharge gap. Voltage is applied to the electrodes causing a strong potential gradient and an electron flow across the gap. These electrons provide the energy to disassociate the oxygen molecules in the oxygen containing gas, leading to the formation of ozone. Higher voltages, higher electrical frequencies, and smaller separation distances between electrodes lead to more effective ozone generation. Increasing the effectiveness of an ozone generating device by optimizing these variables requires high performance dielectric materials that will withstand high electrical stress, elevated operating temperatures, and ozone rich environments without failure over extended duration.
A variety of different materials have been used in the dielectric component of a corona discharge unit, including aluminum oxide, glass, ceramics, and polymers. The range of materials used to form the dielectric component of ozone generation devices varies widely, because there is a broad range of operating environments, such as those for use with water purification systems, air cleaners, and internal combustion engines.
Since much of the electrical energy input to a corona discharge ozone generator—as high as 85%—is converted into heat, the dielectric component must be made of a material that possesses high thermal stability both physically and chemically under rigorous heat cycles and harsh chemical environments, ideally over great lengths of time. Despite a substantial number of different devices formed from a substantial number of different materials being taught or disclosed, few have resulted in a commercially viable material, particularly one intended for use with the combustion of hydrocarbon fuels. One major deficiency of prior dielectric materials relates to their loss of dielectric strength at elevated temperatures, under high electrical stress, and in an ozone rich environment. For example, materials like alumina are subject to cracking or flaking and electrical failure. Glass and plastics tend to become friable under the harsh conditions of a high performance ozone generating unit. This friability then results in premature failure of the device.
Breakdown of the dielectric material in an ozone generation device can cause a variety of problems, including the possibility of dielectric particulate material being carried into a combustion chamber.
The development of an adequate material and process used to create well performing dielectrics will result in energy savings and reduced pollution when applied to diesel engines and other applications where ozone discharge units are used.
The present invention is directed to overcoming these and other deficiencies in the art.